CN110361999A - Active optics micro-displacement sensor signal processing system and method based on DSP - Google Patents

Abstract

The invention discloses a signal processing system and method of an active optical micro-displacement sensor based on DSP. The system includes a power supply module, an AD conversion module, a storage module, a DSP and a display module. The method includes: the power module converts the voltage to supply power to other modules; the DSP controls the AD conversion chip to work, and converts the analog signal modulated by the micro-displacement sensor into a digital signal; the DSP reads the AD converted digital signal and stores it in a storage module; the DSP Demodulate the digital signal to obtain the micro-displacement signal and store it in the storage module; DSP filters the demodulated micro-displacement signal and stores it in the storage module; the filtered micro-displacement data is sent to the host computer through the serial port for processing. display and subsequent processing. The invention realizes the processing of the active optical micro-displacement sensor signal through the digital signal processing method, performs real-time demodulation and filtering processing on the modulated noise-containing micro-displacement signal, and displays the micro-displacement data in real time, with high overall processing speed and high precision.

Description

Signal processing system and method of active optical micro-displacement sensor based on DSP

technical field

The invention belongs to the field of digital signal processing, in particular to a DSP-based active optical micro-displacement sensor signal processing system and method.

Background technique

As a new discipline, digital signal processing is a discipline formed thanks to the rapid development of computer science and information science, and plays an increasingly important role in the application of various fields. Briefly summarized, digital signal processing uses a sequence (digital sequence or symbol sequence) to represent a signal, and the sequence is processed by general-purpose or special-purpose digital signal processing equipment to extract useful information for application. Methods of processing include filtering, transformation, compression, enhancement, estimation, and the like. Compared with analog signal processing, digital signal processing has great advantages in terms of speed, flexibility, accuracy, research and development costs, and environmental requirements. It can replace most functions of analog devices, so it plays an increasingly important role in today's signal applications. The realization platform of digital signal processing is the digital signal processing system. For example, the use of a computer, a digital signal processor (DSP) or a dedicated integrated circuit can be called a digital signal processing system.

In the early signal processing system, signal processing was mainly realized by analog equipment. However, in some practical applications, it is often necessary to record the data on a magnetic tape and then process it on a large digital computer. Analog devices have the disadvantages of poor reliability and flexibility, and it is not easy to implement some complex algorithms, while computers are both flexible and fast, so before using analog devices to form a processing system, people are used to computer It is an early form of digital method to realize signal processing with high complexity.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a DSP-based active optical micro-displacement sensor signal processing system and method.

The technical solution for realizing the object of the present invention is: a DSP-based active optical micro-displacement sensor signal processing system, including a power supply module, an AD conversion module, a storage module, a DSP and a display module;

The AD conversion module is used to convert the analog signal modulated by the micro-displacement sensor into a digital signal;

The DSP is used to control the work of the AD conversion module, demodulate and obtain the micro-displacement signal, filter the demodulated signal, and communicate with the host computer;

the storage module for storing signal data;

The display module is used to display the micro-displacement data in real time;

The power module is used to provide the required voltage for all the above modules.

The signal processing method of the active optical micro-displacement sensor based on DSP includes the following steps:

Step 1. The power module converts the input 5v voltage into 3.3v and 1.9v to supply power to other modules;

Step 2, the DSP controls the AD conversion chip to work, converts the analog signal modulated by the micro-displacement sensor into a digital signal, and stores it in the AD chip register;

Step 3, DSP reads the digital signal after AD conversion and stores it in the storage module;

Step 4, DSP demodulates the digital signal, obtains the micro-displacement signal and stores it in the storage module;

Step 5. The DSP filters the demodulated micro-displacement signal and stores it in the storage module;

Step 6. Send the filtered micro-displacement data to the upper computer through the serial port for display and subsequent processing.

Compared with the prior art, the present invention has the following significant advantages: 1) The present invention realizes demodulation and filtering of the input modulated noise-containing micro-displacement signal to obtain an ideal useful signal, and displays the micro-displacement signal in real time through the display screen. The overall system design of displacement data; 2) Convert the micro-displacement analog signal into digital signal, and use DSP for data processing to improve the data processing speed, thereby improving the real-time performance of the system; 3) Using the fast Fourier method in the frequency domain signal processing method The leaf transformation method processes the micro-displacement signal, with small calculation amount and fast calculation speed; 4) In view of the characteristics of small change and high precision of the micro-displacement signal, a high-precision AD conversion chip is added to the system to improve the accuracy of signal processing.

Description of drawings

FIG. 1 is a schematic diagram of the composition and structure of the signal processing system of the active optical micro-displacement sensor based on DSP of the present invention.

Fig. 2 is the hardware circuit diagram in the signal processing system of the active optical micro-displacement sensor based on DSP of the present invention, wherein (a) is a circuit diagram of a power supply module, (b) is a circuit diagram of an AD conversion module, (c) is a circuit diagram of a storage module, and (d) is the DSP circuit diagram, and (e) is the communication circuit diagram between the DSP and the host computer.

FIG. 3 is a schematic diagram of signal demodulation in the signal processing system of the active optical micro-displacement sensor based on DSP of the present invention.

FIG. 4 is a flowchart of the filtering algorithm in the signal processing system of the active optical micro-displacement sensor based on DSP of the present invention.

Detailed ways

In conjunction with Fig. 1, the active optical micro-displacement sensor signal processing system based on DSP of the present invention includes a power supply module, an AD conversion module, a storage module, a DSP and a display module;

The AD conversion module is shown in Figure 2(b), which is used to convert the analog signal modulated by the micro-displacement sensor into a digital signal;

As shown in Figure 2(d), DSP is used to control the work of the AD conversion module, demodulate to obtain micro-displacement signals, filter the demodulated signals, and communicate with the host computer as shown in Figure 2(e);

The storage module is shown in Figure 2(c), used to store signal data;

Display module for real-time display of micro-displacement data;

The power module shown in Figure 2(a) is used to provide the required voltage for all the above modules.

Further preferably, the AD conversion module is connected with the DSP through an SPI serial peripheral interface, and the DSP and the display module are connected through an RS232 serial port.

Exemplarily and preferably, the power supply module specifically adopts PS767D301 power supply chip; the storage module specifically adopts IS61LV25616SRAM chip; the AD conversion module specifically adopts ADS1256 conversion chip; and the DSP specifically adopts TMS320F28335 chip.

A DSP-based active optical micro-displacement sensor signal processing method, comprising the following steps:

Step 1. The power module converts the input 5v voltage into 3.3v and 1.9v to supply power to other modules;

Step 2: The DSP controls the AD conversion chip to work, converts the analog signal modulated by the micro-displacement sensor into a digital signal, and stores it in the AD chip register. The AD conversion chip adopts four-wire system (clock signal line SCLK, data input line DIN, data output line DOUT and chip select line CS) SPI communication mode. ADS1256 can only work in slave mode of SPI communication, and control ADS1256 on-chip through DSP The registers can be read or written through the serial port. CS must be kept low during serial communication. In the SPI transfer process, data is sent and received synchronously, and SCLK moves synchronously with DIN and DOUT. DIN combined with SCLK is used to send data to ADS1256, valid on the falling edge of SCLK; DOUT combined with SCLK is used to read data from ADS1256, valid on the rising edge of SCLK.

Step 3, DSP reads the digital signal after AD conversion and stores it in the storage module;

Step 4, DSP demodulates the digital signal, obtains the micro-displacement signal and stores it in the storage module;

Step 5. The DSP filters the demodulated micro-displacement signal and stores it in the storage module;

Step 6. Send the filtered micro-displacement data to the upper computer through the serial port for display and subsequent processing. The DSP sends the micro-displacement data to the upper computer through the MAX3232 chip and the RS232 serial port.

Exemplarily and preferably, the synchronous demodulation method is specifically adopted for demodulation of the digital signal in step 4, as shown in FIG. 3 .

Further, in conjunction with Fig. 4, the filtering in step 5 is specifically frequency domain low-pass filtering, including the following processes:

Step 5-1, perform discrete Fourier transform on the input noisy signal x(n), the formula used is:

W _N =e ^-j2π/N

In the formula, N is the number of discrete Fourier transform points, X(k) is the discrete Fourier transform result, and W _N is the phase factor;

Step 5-2, using the symmetry and periodicity of the phase factor W _N to simplify the discrete Fourier transform, implement FFT transform, and obtain the frequency domain signal X(k);

Step 5-3, perform low-pass filtering on the frequency domain signal X(k), the cutoff frequency is f Hz, where f is the frequency of the displacement signal;

Step 5-4: Perform inverse FFT transformation on the filtered X(k), that is, obtain the filtered micro-displacement signal y(n) as:

The invention realizes the processing of the signal of the active optical micro-displacement sensor through the digital signal processing method, performs real-time demodulation and filtering processing on the modulated noise-containing micro-displacement real-time signal, and displays the micro-displacement data in real time. The overall processing speed is fast and accurate. high.

Claims (6)

1. a kind of active optics micro-displacement sensor signal processing system based on DSP, which is characterized in that including power module, AD conversion module, memory module, DSP and display module；

The AD conversion module, for the analog signal modulated through micro-displacement sensor to be converted to digital signal；

The DSP, for controlling AD conversion module work, demodulation obtains microbit shifting signal, is filtered to the signal after demodulation And it is communicated with host computer；

The memory module is used for stored signal data；

The display module is used for real-time display micro-displacement data；

The power module, for providing required voltage for above-mentioned all modules.

2. the active optics micro-displacement sensor signal processing system according to claim 1 based on DSP, the AD conversion Module is connected with DSP by SPI Serial Peripheral Interface (SPI), and DSP is connected with display module by RS232 serial ports.

3. the active optics micro-displacement sensor signal processing system according to claim 1 or 2 based on DSP, feature It is, the power module specifically uses PS767D301 power supply chip；The memory module specifically uses IS61LV25616 Sram chip；The AD conversion module specifically uses ADS1256 conversion chip；The DSP specifically uses TMS320F28335 core Piece.

4. a kind of active optics micro-displacement sensor signal processing method based on DSP, which comprises the following steps:

The voltage that the 5v voltage of input is converted to 3.3v and 1.9v is other module for power supply by step 1, power module；

Step 2, DSP control AD conversion chip work, are converted to digital signal for the analog signal modulated through micro-displacement sensor, And it stores into A/D chip register；

Step 3, DSP read AD conversion after digital signal and be stored in memory module；

Step 4, DSP demodulate digital signal, obtain microbit shifting signal and are stored in memory module；

Step 5, DSP are filtered the microbit shifting signal after demodulation, and are stored in memory module；

Filtered micro-displacement data are sent to host computer by serial ports by step 6, carry out display and subsequent processing.

5. the active optics micro-displacement sensor signal processing method according to claim 4 based on DSP, feature exist In synchronous demodulation method is specifically used described in step 4 to digital demodulation signal.

6. the active optics micro-displacement sensor signal processing system according to claim 5 based on DSP, feature exist In filtering described in step 5 is specially frequency domain low-pass wave, including following procedure:

Step 5-1, FFT transform is carried out to the signals and associated noises x (n) of input, obtained frequency domain signal X (k)；

Step 5-2, low-pass filtering is carried out to frequency domain signal X (k), cutoff frequency is f Hz, and wherein f is shift signal frequencies；

Step 5-3, FFT inverse transformation is carried out to filtered X (k), that is, obtains filtered microbit shifting signal y (n).